A baby Woolly monkey clings onto its mother.

Monkeys climbing on telephone wires.

Monkeys climbing up a pyramid covered in fruit and eating from it.

Close-up shot of the face of a female Guianan black spider-monkey as it eats.

An active Woolly monkey climbs from branch to branch on a tree.

Close-up shot of the face of a Woolly monkey.

Monkey Mia, Australia: Air view travelling over peninsula with steep cliffs and waves breaking on the shoreline.

A Woolly monkey hides behind a thick branch, looking around suspiciously. It then moves onto a nearby branch, with its baby hanging from its back.

Indonesia: Proboscis Monkeys eating and looking after babies within an zoo enclosure in Java

Monkey Mia, Australia: Air views of waves crashing against cliffs with visible strata layers in the rocks.

A Woolly monkey sits on thick branch, looking down, then crawls along the branch.

A group of guianan black spider-monkeys feeding and playing.

Monkeys sitting on a market stall, eating the food on offer.

Japan: Monkeys sit in a line on the roof of a hut within a monkey enclosure. One is very obese, it gets up and walks down the roof onto a raised bank.

Monkeys climbing around a market stall, eating the fruits on offer.

An active Woolly monkey climbs along a thick tree branch and jumps across to another branch.

A Woolly monkey climbs onto a thick branch. Its baby is clinging onto it. The monkey moves along the branch.

A Woolly monkey plays with the baby of another monkey. The baby is clinging onto its mother. The mother then wanders off with its baby.

A Woolly monkey scratches its leg. When it turns around, its baby is seen clinging onto its back. The monkey then crawls away with its baby attached to its back.

Close-up shot of a female Guianan black spider-monkey feeding.

Monkeys climbing down a telephone pole.

Close-up shot of the face of a baby Woolly monkey.

A Woolly monkey crawls along a branch. Its baby is clinging onto its side. The monkey sits down on the branch for a moment, then gets up to continue moving along the branch.

Two adult Woolly monkeys sit on a thick branch. One of the Woolly monkeys plays with the baby of the other monkey. The baby is clinging onto its mother.

Monkey Mia, Australia: Air view of cliffs on edge of peninsula and deep blue sea with waves breaking against the cliffs.

A baby Woolly monkey clings onto the back of its mother.

Side shot of a silverback mountain gorilla sits in a forest, picking at leaves to eat, in the Virunga National Park, Democratic Republic of Congo.

A silverback mountain gorilla starts to climb a tree in the Virunga National Park, Democratic Republic of Congo.

Rwanda: A baby gorilla on its mother's shoulder in a forest. The mother and baby put their faces together in a tender gesture.

An Eastern chimpanzee baby dangling from a tree by its arm as it chews a small branch.

A silverback mountain gorilla looks around the surrounding dense vegetation in the Virunga National Park, Democratic Republic of Congo.

A silverback mountain gorilla in the Virunga National Park, Democratic Republic of Congo, peers around the dense vegetation in which it stands.

A silverback mountain gorilla sitting in dense vegetation in the Virunga National Park, Democratic Republic of Congo. Flies fly around its head.

Side shot of a silverback mountain gorilla sitting in dense vegetation in the Virunga National Park, Democratic Republic of Congo. Flies fly around its head.

Rwanda: A baby mountain gorilla climbs on its mother's back.

Back shot of a silverback mountain gorilla walking into dense vegetation in the Virunga National Park, Democratic Republic of Congo.

A family of Eastern chimpanzees relaxing in a forest clearing in the Gombe National Park, Tanzania.

A silverback mountain gorilla hides behind a thick layer of plants in the Virunga National Park, Democratic Republic of Congo.

Close-up shot of a family of Eastern chimpanzees relaxing in a forest clearing in the Gombe National Park, Tanzania. The baby chimpanzees are very restless and are pestering their parents. One of the baby chimpanzees is climbing all over its parents and ends up lying on the mother.

A silverback mountain gorilla chews leaves and picks at other plants in the Virunga National Park, Democratic Republic of Congo.

A shy silverback mountain gorilla crawls backwards into dense vegetation in the Virunga National Park, Democratic Republic of Congo.

A silverback mountain gorilla in the Virunga National Park, Democratic Republic of Congo, picks at leaves and vines and chews them while lying down.

A silverback mountain gorilla in the Virunga National Park, Democratic Republic of Congo, sits in dense vegetation, scratching its face. It then gets up and wanders off.

A male eastern chimpanzee walks into a clearing in a forest and sits down, in the Gombe National Park, Tanzania.

A silverback mountain gorilla in the Virunga National Park, Democratic Republic of Congo, looks curiously into the camera then hides behind the dense vegetation surrounding it.

A silverback mountain gorilla sits calmly in dense vegetation, picking at leaves to eat, in the Virunga National Park, Democratic Republic of Congo.

A family of Eastern chimpanzees relaxing in a forest clearing in the Gombe National Park, Tanzania. When they wander off, the baby chimpanzee hangs onto its mother.

Close-up shot of a restless baby Eastern chimpanzee lying on the ground.

Close-up shot of a family of Eastern chimpanzees relaxing in a forest clearing in the Gombe National Park, Tanzania. The baby chimpanzees are very restless and are pestering their parents.

A silverback mountain gorilla picks a handful of leaves and chews them in the Virunga National Park, Democratic Republic of Congo.